Woodward DPG-2201-00 Series, Руководство пользователя

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Manual 36523B DPG-2201-00X Digital Controllers
Woodward 15
For example, suppose Set Speed A is 3300 Hertz and Set Speed B is at 3960
Hertz. The controller is currently controlling the engine at 3300 Hertz (Set Speed
A), when Set Speed B becomes the active target speed. It is desired that the new
speed of 3960 be reached in precisely 2 seconds. The following formula
determines the value needed by Accel Rate to increase the engine speed from
Set Speed A to Set Speed B in 2 seconds.
[(Set Speed B) – (Set Speed A)] / (N seconds) = accel_rate_value in Hertz per
second
[3960 – 3300] / 2 = 330 Hertz per second
3.15 Decel Rate (optional)
The Decel Rate specifies how fast the controller should decrease the engine’s
speed when a new lower target speed is made active. The parameter value is
specified in MPU (magnetic pickup) Hertz per second based on the following
formula.
[(higher_speed_in_Hertz) – (lower_speed_in_Hertz)] / (ramp_time_in_seconds) =
decel_rate_value
For example, suppose Set Speed A is 4170 Hertz and Set Speed B is 3475 Hertz.
The controller is currently controlling the engine at 4170 Hertz (Set Speed A),
when Set Speed B becomes the active target speed. It is desired that the new
speed of 3475 be reached in precisely 1.5 seconds. The following formula
determines the value needed by Decel Rate to decrease the engine speed from
Set Speed A to Set Speed B in 1.5 seconds.
[(Set Speed A) – (Set Speed B)] / (N seconds) = decel_rate_value in Hertz per
second
[4170 – 3475] / 1.5 = 463 Hertz per second
3.16 Startup Rate (optional)
This parameter is used to achieve a smooth controlled engine start. On diesel
engines, this feature is also useful for minimizing exhaust smoke at startup. When
used in combination with the Idle Speed and Idle Hold Time, a brief warm-up cycle
can be programmed.
The startup rate specifies how fast the controller should increase the engine
speed when the engine is started. The rate value indicates Hertz per second. The
formula to use for determining a precise Startup Rate is shown below.
[(final_target_speed_in_Hertz) – (crank_speed_in_Hertz)] /
(ramp_time_in_seconds) = startup_rate_value
The controller increases the engine speed from the engine’s crank speed to the
active target speed at the rate specified. The controller will bring the engine to the
Idle Speed for the Idle Hold Time then continue increasing the engine speed at
this same ramp rate until the engine reaches the selected target speed (Set
Speed A or Set Speed B).
Exception 1: In cases where the target speed is less then the
Idle Speed and the Idle Hold Time is nonzero, the startup
ramp sequence ends when the Idle Speed is reached. Then
the Decel Rate is used to ramp the engine speed down to the
target speed from the Idle Speed.